import java.util.Random;
import java.util.Scanner;
/*
*
* 随机验证码
* */
public class test10 {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        String code=CreatCode(n);
        System.out.println("随机验证码为"+code);
    }
    public static String CreatCode(int n){
        //随机5位验证码 每一位都是一个随机数
        String code="";
        Random r=new Random();
        for (int i = 0; i <n; i++) {
            //012
            int type=r.nextInt(3);
            switch (type){
                case 0://大写AZ 65 90
                 char daxie=(char)(r.nextInt(26)+65);
                 //拼接
                    code+=daxie;
                    break;
                case 1:
                  char xiaoxie=(char)(r.nextInt(26)+97);
                  code+=xiaoxie;
                    break;
                case 2:
                    int number=r.nextInt(10);
                    code+=number;
                    break;
                default:
                    break;
            }
        }
        return  code;

    }
}
